


This is My Scar, Not My Birthright

by chasingblue57



Series: scars & birthrights [1]
Category: The Flash (TV 2014)
Genre: Alternate Universe - Soulmates, F/M, Soulmate-Identifying Marks
Language: English
Status: Completed
Published: 2016-01-25
Updated: 2016-01-30
Packaged: 2018-05-16 02:27:22
Rating: Not Rated
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 10,453
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5810026
Author URL: https://archiveofourown.org/users/chasingblue57/pseuds/chasingblue57
Summary: <blockquote class="userstuff">
              <p>Twelve neat crimson lines tie them together, even years before they meet, but perhaps it's the shared heartache and loss that truly make them soul mates.</p>
            </blockquote>





	1. This is My Scar

She's probably three before she really notices it, eight or nine before she begins to understand what it means and twelve before she truly comes to terms with the weight it carries, the significance of that neat little hexagon with three double sides and three branching lines, sprawled across the inside of her wrist. It's a deep crimson, a captivating color that never goes unnoticed, especially against the pale contrast of her skin. It's also when she's twelve, breezing through AP biology, that she finally connects the literal meaning of those little red lines (something more practical than soul mates and destiny and true love): they form the chemical symbol for dopamine (she's still a little hopeful then, still bright eyed and optimistic-it's a few years before she comes to find the symbol ironic).

Like most children, Caitlin spends her younger years absolutely fascinated by the tattoo, tracing the lines with eager fingers and dreaming wistfully of who might wear its match--the implication of watch that match means changes as she does (a best friend, a boyfriend, until she finally comes to understand what a soul mate really means: a friend and a love and a partner). She builds her understanding gradually, as children tend to, by watching her parents, smiling at the way her mother and father (two blue quill pens) are always happy, laughing and bright and so warm, giving their love to each other as readily as they do her. They weather every storm together and in doing so, shore up their daughter's conviction that one day she and her soul mate will do the same: two crimson chemicals ready to take on the world.

But as she grows, the rest of the world begins to edge in, and slowly the excitement of that little red dopamine symbol begins to wane, becoming as much a cause for concern as it once was for fascination.

The foundations begin to lay themselves out early. Caitlin's barely ten years old when she begins to realize that she is so much more than just 'smart as a whip' as her father likes to say: she is unnaturally bright and years ahead of her age group. So, of course, they remedy that with skipped grades and advanced courses and she becomes the a pre-teen in a world that was not built for her (the material is still too slow, too effortless and the company is both too simple and far too complicated). She moves into AP and college credit classes and it still comes easily but it's interesting at least.

She wishes she could say the same for friendships. Caitlin's too young, too smart and it leaves her alone and isolated.

If her mark were somewhere hidden, or something less vibrant, it might be easier but instead it's so clearly visible that it gives her classmates an easy target, gives them something else to mock. The older girls in her classes, burning with frustration and jealousy, tell her she'll never find her match, that her mark is proof that she'll grow old and gray with chemistry sets instead of a soulmate. As stubborn as she is smart, Caitlin tells them they're wrong, dark eyes blazing and sharp, but when they turn back to the lecture, Caitlin traces the pattern, hidden beneath the top of her table, and tunes out her teachers and she wonders (and she breaks, piece by piece, like electrons being stolen away to create un unstable, unhappy molecule),

Caitlin goes to college at fourteen and everything gets a little bit harder: the science, the students, the soul mate thing. The science at least is a challenge she dives into willingly (enthusiastically, whole heartedly: she's a medical doctor with an emphasis in bioengineering by twenty, adds a degree is chemistry by twenty two).

Helping other people, wading through research, searching for ways to change the world: they give her great distraction and for the first time in her life she is well and truly challenge by what she's doing. Fortunate, probably, because her heart remains otherwise unoccupied and that is a challenge she cannot control--her mark is still bright and blazing, obvious to all and yet no one steps forward baring its twin.

She tries not to be disappointed, focuses on all the good she might do, but all around her, her 'peers' (most half a decade her senior) are delighting in the discovery of so much more than just science: they find their soul mates and their happiness and their lives fall into perfect place. By the time Caitlin is twenty two and finishing the last of her schooling, she begins to give up on finding her soul mate entirely and starts wearing a watch over the sprawling crimson lines. Maybe, she tells herself, it won't hurt so badly if she just thinks no one is stepping forward because they don't realize they're meant to be together.

(It still does hurt, but it becomes much easier to pretend when those precise little lines are no longer staring her in the face.)

Dr. Harrison Wells hires her the day she graduates with her PhD and again it gets a little easier: Caitlin lets herself get so caught up in the whirlwind of moving to Central City and working at S.T.A.R. Labs that for the first time in a long time, she actually does forget to think about her soul mate mark and who might likewise wear it. (That wears away of course, so she tells herself that maybe the person she's looking for is somewhere here, just waiting to be run into and that her new job and the move are all steps toward the destiny she's simply lived too far from until now). It helps for a little while, buoys some distant faith.

About a year into her new life, her new job, her (slowly deflating) newfound optimism, Dr. Wells calls together a special team for a special project: his particle accelerator, the culmination of his vision (a vision he'd thrown himself into when a beautiful woman with a golden atom across her should blade left him of whatever waits on the other side of this world--something everyone knows but no one mentions). He explains their refocus, that they will be making new hires for this specific project and tasks them with beginning to research for their individual duties within the overview of this heady new undertaking.

Excited, Caitlin does what she always does and throws herself into her work, researching and planning and prepping. It takes six months of interviews, team meetings and reading upon article before they really start the project but she's fascinated and busy and largely content. Working with this new, smaller group (which is slowly getting bigger as time goes by), she finally begins to feel like she fits in, like she belongs to something that's bigger than herself and she thinks, maybe, it's a little bit like what it must feel like to have a soul mate. She's actually making friends, real friends like Cisco Ramon who is also too young for the degrees that follow his name, and for the first time in her life she begins to think that it's okay if science really is her soul mate: if she can have science and these people, this purpose, that might just be enough.

She meets Ronnie Raymond the day the particle accelerator team moves into the lower part of the labs and although she doesn't know it, everything starts to change.

Ronnie is handsome and he smiles constantly. Like so many at the lab, he's too young for his job (engineer) but he's still two years old tan she is and he cracks jokes like it's his mission to keep everyone from getting to serious about the biggest scientific breakthrough in living history.

Caitlin doesn't dislike him at all but she also doesn't begin to like him immediately either--he's bolder and louder than she's ever dreamed of being, but he's also thoughtful and intelligent and once he befriends Cisco, she finds herself dragged along for the ride.

It isn't hard to start falling for him after that: he pushes her in ways people have never done before (kindly, eagerly, with a sparkle in his eye and a smile on his lips, always egging but never taunting, calling on her stubborn side to meet his every challenge). It doesn't hurt that those big grins and casual touches tell her that Ronnie is falling for her too (her assurance bolstered by Cisco, who drops increasingly ridiculous hints to them nth until Ronnie finally 'mans up' and 'asks her out already'). He's surprisingly shy when he does it, hesitant in a way she's never seen, and it's that more than anything that has her stumbling out a 'yes' around the smile she wears.

Their first date is at the natural history museum. Ronnie takes her there before dinner and they spend an entire afternoon winding through the exhibits, talking about whatever comes to mind. By the time they make it to dinner, Caitlin finds her eye sweeping every inch of exposed skin she can find, hoping to catch a glimpse of dark red (she leaves a bracelet over her own tattoo, equal parts fear and habit while telling herself it doesn't really matter; who cares about theoretically soul mates anyway?) She doesn't see so much as a hint of a line, but she knows not everyone's marks are visible--Cisco's jumble of dusty orange concentric circles are on his shoulder blade after all.

As it turns out, Ronnie doesn't care about theoretically soul mates and Caitlin discovers this a few weeks later, sprawled against eh dark gray sheets of his bed. Her fingers trace the royal blue cog that dominates his left pectoral, the dissonance building against each beat of her heart as she stares at the red of her wrist that is so very far from a match. It's a hollow feeling, like her heart is about to drop out from beneath her, and Ronnie doesn't noticed until her breathing catches. It doesn't take long for him to understand what's wrong, but he just smiles that way he always does, easy and bright and carefree in a way Caitlin has never been, twisting their fingers together and tracing a thumb against the inside of her wrist. "So what?" and then he kisses her mark, unrepentant and tender.

He spends the rest of the day telling her it doesn't matter and the next year proving it to her (he's an engineer, he says: he believes what he sees and what he builds, with his own two hands).

When Ronnie proposes, on the eve of their first anniversary, he tells her that he loves her because he chose her, because she chose him, because they've built what they have together rather than letting fate do it for them. Caitlin loves him so much that she can't even get a 'yes' around her happy tears, so she kisses him instead, in the middle of the museum, and she doesn't think twice about who might wear a crimson chemical against their skin.

Until, of course, everything goes wrong and, in the midst of all that chaos, she finds him: twelve deep red, perfect little lines arranged in a hexagon with a tail and three double sides that set a knife against her heart.


	2. Not My Birthright

He's a quick learner, the kind of kid who notices details that other people miss, even from a young age. As such, the vibrant red tattoo nestled against the ridge of his collarbone catches his fascination early. It's the first color he learns and, according to his smiling mother, the first question he asks: one stubby finger pressed against the mark and his little brow furrowed, saying 'mama' in the same thoughtful, puzzled tone that he'll one day ask all of life's big questions in. His mother scoops him up with a laugh and tells him a story about soul mates and destiny and love. It's a story she'll repeat time and again as he grows up, but he'll never get to hear it as many times as he'd like.

When he's a little older and understands a little better, Barry traces the deep red tattoo studiously, careful fingers smoothing over each of the twelve lines that are as much a part of his skin and his life and his identity as anything else about him (his mother's green eyes, his father's dark hair, his fascination with the way the world works around him.) "How do they work?" he asks his father, time and time again. His dad is a doctor and Barry's sure that he knows absolutely everything.

Everything but this it seems.

When he's six and deemed old enough to mostly understand, his father takes him to their tree house and sits him down for a 'grown up' conversation. Barry's chest hops with excitement, his fingers tapping nervous energy against his knees while Henry explains about soul mates and destiny and love, not unlike his mother has done a dozen times before. And just like he's always done, Barry can't help wanting to know more, to understand, to puzzle and detail out all the pieces of the picture that emblazoned a dopamine symbol against his skin. "But how do they work dad?"

And finally the answer isn't 'I'll explain when you're older'. Not that "I don't know Barry buddy, they just do," is any more satisfying but then his dad starts talking about how he met his mom and Barry's more than a little fascinated. He tells a story about a beautiful young woman in his philosophy class and how he already knew she was his soul mate long before he saw the golden starburst on her side that matched the one on the outside of his left calf.

Barry listens to his father story raptly and in that moment he falls completely in love with someone he doesn't even know: he just knows that he must love them, they must be perfect, because his parents are the best and they're the best together and somewhere out there is his soul mate too. It's a blind and unerring faith that complicates the next 17 years of his life in ways that he cannot begin to imagine (but the worst is yet to come).

Ten months later, a flash of yellow steals into his house in the middle of the night. Crying for help, he finds himself flung into the street and then lightning kills his mother and no matter how many times he tells Officer West what he saw, his father still goes to jail for her death.

It's hard, so very hard, to live without them: without his mother's sunny smiles, his father tousling his hair and call him slugger. He misses their voices and their stories and the warm press of their love all around him. Joe is kind and careful, Iris is bright and outgoing, but they're not his family and it's just not the same. For months he nurses a secret wish: that the lightning hadn't thrown him out, that it had taken him too but every time he thinks that, he finds his fingers lingering over the crest of his clavicle, tracing the mark beneath his shirt while guilt claws his heart. He misses his parents like a constant, gut-wrenching ache, but there's still someone out there who needs him, and it feels selfish to wish he were gone too: what would his soul mate do then?

He lets the little red mark be his driving force, a place to center himself when he misses his parents too much. He reminds himself of the stories they told, the smiles they wore, their twin golden starbursts and their faith that someday he would love someone the same way that they loved each other (and him).

It works out pretty well for a while but he misses his parents more then ever when he realizes he's fallen in love with someone who isn't his soul mate and he doesn't know what to do about it.

He's fifteen and Iris is the most beautiful girl he's ever seen.

She's clever and funny and extroverted in a way that just draws people in. He doesn't understand how she does it, how she manages to be so effortlessly friendly and inviting, but she makes everyone around her feel special and important. She's also brave and kind and, most importantly, she understands and accepts him for who he is (and she believes him, unquestioningly, when he insists that his father is innocent and it's maybe that faith that starts it all in the first place).

But she's not his soul mate and he doesn't know how that's supposed to work. (He had thought maybe she was, for a little while, that maybe his parent's death was some kind of horrible contrivance so that he could know her, and it actually comes as a little relief to learn she isn't. He sees the plum marking when they're fourteen and she wears Joe down enough to let her get a bikini--it's hard to miss the tattoo on the small of her back or the warring relief and regret that crash in his chest).

He's still in love with her though, a feeling that grows and burns and tears at him for years until he finally leaves for college, one year ahead of his age, but still a little too far behind where he could be.

It's easier to forget away at school, where he can separate himself from his past and his feelings and just throw himself into his studies (or so he tells himself, not thinking about the fact that he's chosen to study forensic science with the hopes of one day clearing his father's name). 

He goes to classes, gets a job working as a research assistant and he makes friends who don't know about yellow lightning and dead parents, about the adoptive father who cosigned his mountain of student loans or the adoptive sister he's kind of in love with. He even dates now and then, aided by his roommate but he doesn't find anyone that shares his red lines and if he can't have his soul mate, then he wants Iris and anyone else seems pointless.

He doesn't feel like there can be any in betweens: if he's going to betray the kind of perfect love his parents had, there's only one person he's willing to do that for, and she doesn't love him so it doesn't matter.

Four years pass by in a whirlwind: he studies, he works, he visits home on holidays and texts and Skype’s Iris and Joe and whenever he's back in Central City, he visits his father. Their visits are hard. They tear open wounds that never do more than scab over and every time he leaves Barry can't help but notice the way his father’s fingers always smooth over a particular spot on his left leg: even covered in orange and the color dull with the loss of his Nora, Henry Allen remains drawn to the physical mark her love has left.

He's twenty-one and he's never met anyone with a mark even close to his: no other chemical symbols, no one in quite his shade of startling crimson. He wants to keep the faith, but it wanes with the influx of his loneliness and his desperation to clear his father's name. When he gets the offer for the job with the Central City PD, he decides the best way to move forward is to try and forget.

Barry starts wearing button downs and sweaters. They're more professional but still functional for crime scenes and, most importantly, their collars and layers hide the reminder of his absent love.

Somehow, it gets easier and harder. He loves his work (loves the access to his family case file), is glad to be back in Central City and, even if it's not quite what he wants, can't help but enjoy being around Iris again as she finishes her last year of school. Joe tells him he's welcome to his bedroom, that he's always welcome home, but Barry knows well enough that will only make things worse, so he finds an apartment near by and resolves himself to the exquisite misery of loving someone he's not meant to have.

It's too easy to torture himself though--to interpret from smiles and teasing a meaning that isn't there, to imagine her gaze lingers along his collarbone, that her thoughtful furrow is meant for his crimson and her plum and not the article he's been helping her research for the last two weeks. It's just so easy, so natural and he swears that she must see it too, as she brings him another coffee and scribbles down a few more notes between customers. He laughs at how hard she's working and her eyes roll, all smiles, snipping good naturally about him learning to explain it to her in English.

The night of the particle accelerator event is particular torture as she wheedles him out of work (her dad always a pushover, as powerless against her charm as he is, for such very divergent reasons) and leans against his arm, looking lovely and curious and burning to prove herself up to her professor's challenge. She's all the things he loves best about her, all at once, and so he basks in it and doesn't think about anything else (not soul mates, not destiny, certainly not stupid red lines against his skin or the perfect promise his parents lost in one fell swoop).

It costs him her laptop and his dignity and the predictable track of his future, because he's barely back at the lab when the impossible strikes twice and all he knows is a great shock of pain, a blinding light and then darkness.

He wakes up nine months later, stiff and strange, feeling like he's coming out of an unplanned nap. The light is bright against his eyelids, and even through the skin it burns, but he can't help feeling like he needs to wake up all the same. Somewhere in the distance he hears Poker Face playing, and voices he doesn't recognize, and out of nowhere comes an urgency he doesn't understanding, drawing him up with a gasp.

"Where am I?" he breathes, ragged, barely registering the tug of tubes and wires along his skin before brown eyes invade his vision, bringing with them more bright lights and a soft but steady hand along his arm and shoulder--he has no idea where he is, who they are or what's happening, but his hand comes up unconsciously to uncover the mark even as he fumbles out of bed.

He's so out of it he doesn't notice the way the brown eyes, or the woman behind them, flinches at the gesture, letting the sample cup fall and leaving her companion to reassure calm him.

(He does notice the way he burns, exquisite and terrifying, when her hands press along his skin, checking his muscle tone--he doesn't understand it, but then he doesn't understand much at the moment).

**Notes for the Chapter:**

> And so ends Barry's introductory chapter, where we have a little more canon events intertwined. The last part (which is rather a bit longer) will weave in a little canon again but diverge and continue to concentrate mainly on the relationship between them. Feedback is always appreciated & last part should be out Friday night or so.


	3. but you are everything I need

The love of her life dies on a Tuesday and seven weeks and two days later, she finds her soul mate.

It's the worst kind of Thursday, not that there's been any other kind since the particle accelerator exploded, but this one seems particularly miserable. Caitlin's first to arrive at the lab, tidying up the mess that doesn't exist before she settles at her computer, strong coffee in hand, and begins the tedious task of combing through data and inventory, flipping through invoices and gathering the scattered remains of their lives and their work. Dr. Wells usually arrives at eight, prompt and timely even now, and Cisco scuttles in nearer to nine. They don't laugh or joke like they used to, there aren't enough voices to carry that kind of easiness, but they talk and it's comforting, this tiny piece of normal.

Today though, Caitlin slogs in a little late, more put out than usual given the poor weather. She grumbles through her usual morning routine and barely notices when Dr. Wells is late—it's not until Cisco arrives, loud and curious, that she realizes he hasn't come in at all.

It's enough to make her worry, brow furrowed and frowning, while they debate if they should call. "Maybe he's just having a rough morning," Cisco suggests, likewise looking put out and concerned, though his words and tone convey a degree of optimism that Caitlin has frankly given up on.

"Or maybe something's wrong," she cuts back, sharper then she really should be. Cisco means well, but Caitlin's vision refuses to widen to hope anymore, not when it's all been stolen from her. Her fingers shudder where they clutch her phone. It takes a moment to steady them enough for her thumbprint to register, and then she's scrolling through her contacts, avoiding Ronnie's place at the top of her favorite list with the heart clenching difficulty no amount of practice can abate.

Wells doesn't pick up immediately and her call cuts to voicemail more quickly then it should: she manages something she hopes is intelligible around her chewed lip and shaking hands and barely contains a gasp when the shaking intensifies—just her phone vibrating, Wells texting to say he's coming with a patient this afternoon, asking her to prepare a medical station.

"Do what?" Cisco asks, startled enough to drop his pen.

"He says he's bringing in a patient, and to get ready."

"But he's fine?" He looks the way she feels, wholeheartedly confused and a little anxious.

"I guess?" So they get to work, re-arranging lab space and setting up the medical supplies, beds, machines and protocols that S.T.A.R. Labs had abandoned when they'd narrowed their research focus onto the accelerator. (She feels a little bit at home as Cisco unearths long unused equipment, the tools for the research that had initially drawn her here, but she doesn't get too excited, not when she has no idea why.)

They're more than ready when Dr. Wells calls to say he and their patient and his family are on their way, giving little more explanation than he had before.

Barry Allen rolls into her life unconscious and on a stretcher, flanked by two disgruntled looking EMT's, Dr. Harrison Wells and a middle-aged man and young woman she assumes must be the victim's family. Harrison explains the situation briefly, his words stifled in a way that says there's something more, but the pinch of his gaze says 'don't ask' so she doesn't and miraculously neither does Cisco. All she apparently needs to know is he's in a coma, it's their fault, and the hospital doesn't have the resources or expertise to care for him.

(She feels a little like the man's been dumped in her lap, like maybe Dr. Wells thinks if she looks after him, if she saves him, she'll forget the people she couldn't.)

She gets his medical history in explicit detail thanks to the man (Joe West, adoptive father) and the young woman (Iris West, his daughter) and eventually they seem content enough with how he's settled to force themselves to go home, leaving Caitlin to finish running her own baseline tests.

It's when she's hooking up the last of the heart monitors (replacing the temporary ones he'd been on with their own, newer models) that she pulls up his hospital shirt and freezes, hand tightening around the thin fabric, knuckles white with the force of her grip (as white as her expression, the blood all gone from her cheeks). In the hazy background of her thoughts, she is grateful that both Dr. Wells and Cisco aren’t currently in the lab, both preoccupied with walking the Wests out.

It's been over twenty years since she first noticed the red lines on her wrist, more than a decade since she's taken to covering them with a watch, and a few less since she gave up caring about them and what they meant entirely, but suddenly they're staring her in the face once more—vibrant and familiar, even etched against the unfamiliar collarbone of an unfamiliar male.

In the sleepless nights to follow, she will laugh humorlessly at the irony: that she lost the love of her life only to find her soul mate in a coma she caused; that in losing one person she loves, she’s found another that she should, with absolutely no guarantee that he too won’t be taken away from her (another ghost waiting to haunt the long nights and longer days, another empty echo waiting to strike against the beat of her own battered heart).

 

Caitlin literally has months to try and get used to the sight of her brand against his skin, but it startles her a little bit every time she checks his vitals, frowning at the way his muscles seem to shape slowly when they should really be deteriorating and letting this abnormality distract her (which is perhaps why it's always a shock, she has become astoundingly proficient at ignoring it).

"I just don't understand why his muscles aren't atrophying Dr. Wells. He's been in a coma for nine months." It's definitely a question she's asked before, standing over a clipboard, wearing that same furrowed look that has become her norm. It's mid-morning, she's finished her first round of research and is taking her usual updates on his condition, making the exact same notes she has every day since he was wheeled into her lab and her life, wholly unexpected (and unasked for, in so many ways).

"It's got to be something to do with the explosion," Harrison says as carefully as he's done every time.

The answer is never satisfying, but she nods and goes back to making her perfunctory marks, while Wells heads elsewhere and Cisco ambles in. "No change in sleeping beauty?"

Her eyes roll, unamused. "He has a name Cisco," not that she ever uses it.

"I know, I know," and then there's nothing but clicking keys as they settle back to their separate work—at least until Cisco starts playing Lady Gaga, a little while later.

Caitlin looks up from the report she's reading, "what are you doing?"

"He likes this song," Cisco protests, getting up to walk over to their silent guest. "I saw it on his Facebook page." He takes a bite of a twizzler and nods downward. "I mean, he can hear it right?"

She's already standing opposite him, resisting the urge to shake her head. He does have a point. "Auditory functions are the last to degenerate," she yields, hovering a moment to let her gaze sweep over his bare chest, eyes faltering a little on his collarbone. It's ridiculous, the way anxiety crawls suddenly up her spine, leaving an uncomfortable twist in the pit of her stomach. She shouldn't care, shouldn't really be worried about this stranger, but the longer he lays on a table in their lab, the more anxious she gets about whether he'll wake up (it shouldn't matter, but it does). A sigh slips low from between her lips and she turns to the medical table—the last calm moment for a long time.

Because suddenly the monitors are alive and the lab is filled with their shrill beep at the sound of gasping. She watches it start in slow motion—Barry popping up on the hospital bed, Cisco turning back in shock—and then she slips into doctor mode so quickly it's a little comforting, grabbing a flashlight and clicking it on.

"Where am I?" he breathes, ragged and tugging at his monitors and tubes.  
Caitlin ignores it, calling out vitals and checking his vision, his ears, anything he'll stay steady enough for her to examine with the tools already sitting out. Her heart is racing beneath the authoritative bark of her voice, but it all stutters to a stop when he gets up and his palm settles over the red tattoo.

Caitlin flinches—it's all reality now. She has a soul mate, alive and awake and standing in front of her, somehow standing on his own two feet after nine months in a coma. Cisco rushes in where she falters, filling in details and trying to calm him down, telling him where he is and what's been going on. It gives her the time she needs to catch her breath again, to focus and remind herself to be a doctor first (the rest of this tangled mess can surely wait).

"Lightning gave me abs?" He sounds as puzzled as she's been for months, and it's the last bit she needs to jumpstart her ability to process and deal, leading him back toward the medical table with careful hands against his shoulders, pressing against the muscles as if to check that yes, they are still real. Her fingers burn when they stray against the dopamine symbol, and she knows by the widening of his eyes that Barry feels it too, sudden and surprising and startling them both, but then Dr. Wells walks in and the reaction dies momentarily between them.

Caitlin quickly volunteers to go find him clothes, leaving the bulk of the explaining to Dr. Wells (aided by Cisco's unscientific but amusing asides) and then avoids his suddenly curious, lingering gaze when she walks back in and hands him the sweats.

She realizes too late that in their haste to calm him, her watch had fallen off, leaving her wrist bare and the mark visible. Looking up, their eyes catch and there's something both faraway and immediate in the even green of them, seeing straight through her without really knowing anything about her—she fights a shiver and shakes her head. "Later," escapes before she can think better of it (there are most tests to do, more to learn and too many people around—these are the lies she tells herself, quick and casual: any excuse to put off this conversation she’s not really sure she can have). Despite herself, something in her heart settles a little at his nod, the tiniest curve of a smile and the curiosity lingering behind his eyes.

 

Later doesn't come for several days because her soul mate has superpowers and the fallout of that fact takes a great deal of precedence that affords them no time alone to talk (and if she facilities that a little, she blames the way his eyes linger and burn through her every expression all too often). But a chance does, inevitably, come.

Barry is sprawled across the hospital bed, a little too pale, but awake and grimacing at the pain of his relatively (for him apparently) minor injury. Hovered above him, desperately willing Cisco not to wander away, Caitlin stitches the cut closed. "I know you can heal quickly," she scolds, annoyed and voice thin in a way that it shouldn't be (she doesn't feel for him what she felt for Ronnie, she can't, but there's a gravity about him that she knows she can't quite escape), "but you really need to learn how to stop without tearing yourself apart."

He grits his teeth against the piercing needle and the unapologetic way Caitlin slides it through his skin—she doesn't bother to waste the analgesic: it wouldn't do much anyway. "I'm trying," tumbles out, a little breathless and strained.

It does give her pause, brow crinkling and something in her chest loosening a bit. "I know." He's so remarkably good: kind and thoughtful, if reckless in a way that sets her nerves on edge. His whole life has turned upside down and all he wants to do is learn how he can use it to make things better again (she's not sure she could feel that way; not sure she does, now that the opportunity presents itself).

It's not really rational, but she reaches for the topical analgesic anyway, using a gloved finger to spread it over the still-open seam of his gash before tugging the needle through once more. Barry's metabolism burns it away quickly, but she's only a few stitches from being finished and she can just keep reapplying. The whole process takes a bit longer for it, but he doesn't squirm in his seat as much as before, even wears a suddenly soft look as she works, trying to watch her from beneath his lashes while making his focus appear to be resolutely on his (somewhat melted) sneakers.

Caitlin ignores it, finishes tying the last knots and then carefully scrubs away the last of the iodine before walking towards her desk without a word. He's sure that means stay put and don't do anything stupid, but he's not sure watching her unabashedly wouldn't quality as 'stupid' to her.

"What?" She asks, a few moments later, when she feels his eyes and has finished jotting down the notes on his chart.

The slope of his gaze is thoughtful, eyes dark and intense as he regards her. "I just noticed that you don't smile too much," comes out a lot more tentative than he means it; a careful venture forward now that they're finally alone (Wells gone who knows where; Cisco down to make repairs on his suit).

"Two months after an accident destroyed my career and killed my fiancé, my boss put my soul mate on my medical table," she's a little sharp, all edges and hard lines—not unlike the mark that draws them together, dark eyes fierce and defensive where they meet his. "And after being in a nine month coma, he wakes up and turns out to be a reckless superhero...this blank expression pretty much feels like the way to go."

His face crumbles in on itself (God, he's the type to wear his heart on his sleeve) and there's a tug, a heady undercurrent, of guilt. None of this is Barry's fault. But then he gentles, seems to resolve himself, and nods. "I get it you know," there's a deep sigh, a thoughtful pause. "My mother was murdered when I was seven and they charged my dad, even though I know he didn't do it." This is news; it startles her and draws her gaze back to his, eyebrows climbing with surprise. She knew there had to be some story, when Joe West had claimed his medical power of attorney, but she had never felt it appropriate to ask. "I know how it feels to have your whole life turned around."

He doesn't say he's sorry and she appreciates that (it doesn't change anything, doesn't make anything hurt less) but she nods a little, acknowledging the sentiment that lingers (empathy, understanding, not sympathy or pity or judgment).

"I'm not going to push you," he adds, after a lengthy pause and Caitlin doesn't miss the way his eyes flicker to her wrist, covered again. "But I'm here if you ever want to talk."

It feels like there's a whole lot more than just shared loss echoing along the edge of his words, the whole tangled list of implications brought on by their shared marks, but if he has more to say, he loses his chance to say it. Cisco walks back in barely a heartbeat later, asking if he's ready to come down stairs and help with suit modifications.

He defers to her, a silent flick of his eyes and tilt of his head. Caitlin doesn't bother to examine how easily she can already read his non-verbals, just gives an exaggerated sigh (glad to fall back into doctor mode) and shoos them both out.

 

She feels his eyes on her from across the lab, a prickling sensation that dances along the notches of her spine and settles at her neck, so steady she can't possibly ignore him forever (which, determined to finish what she’s working on, is all she really wants). She tries to though, stares at her computer screen with an intensity that Cisco would joke burns holes, scrolling through page upon page of notes, the routine broken only by an occasional edit and the overshadowing, overwhelming weight of his stare. Eventually though, she breaks and heaves a beleaguered sigh, realizing that somewhere along the way his scrutiny won out—she's read the same paragraph three times and she's still not sure what it says. "Yes Barry?" The words spill out like warm honey, quick but easy, too sweet off her tongue.

Her concentration is admirable (endearing is a word that skirts, tied to a fond smile, through the back of his thoughts) but clearly floundering: Barry buries a smirk at the set of her shoulders, the way tension builds steadily the longer he watches her. He doesn't mean to be obnoxious, not at first anyway, but he can't help himself. He's confined to the bed, shackled there by mending bones and her exhaustive anxiety on his behalf (which feels increasingly like it means something, hope growing in his chest), and it shouldn't intrigue him, shouldn't make him want to know more, but he does. He wants to peel back the layers of Dr. Caitlin Snow and turn over the reason she's still fighting this so hard, dancing passionately on the edge of waning apathy and waxing concern. He's trying not to push her, but he try though he might, he just can't fight off this curiosity, this thing that buzzes almost tangibly beneath his skin, demanding to know her better.

"What's your favorite color?" He asks, the first thing he thinks of when her mouth finally drips his name and those dark eyes (murky with agitation) turn the force of their heat onto him. It's a ridiculous question, so far from the forefront of the ones he wants to ask, but they've made too much ground the last few months to toss it aside on questions she's not ready for. This feels safe: lighthearted and playful, wrapped up with the curl of his smile and his gaze holding hers.

It doesn't hurt when her nose wrinkles a little, and her forehead slopes with confusion, her focus roving over his features careful and calculated, as if trying to guess at some game he's playing.

Barry doesn't fold, just smiles and shrugs, absent and casual (even if he is, beneath the surface, waiting with bated breath for any each and every bit of personal detail she'll willingly give up).

"Red," she decides, dragging it out like it's a question rather than an answer—like maybe it's something she never thought of before and it's scarcely out of her mouth when his eyes track, quick as a flash, to the covered spot on her wrist he knows holds her mark (his mark; their mark). His chest swells and smolders, a feeling that reaches right to the tips of his toes. "You?"

A grin, disarming. "Same," because it always has been, since that first time he looked down and saw it etched in his skin, twelve lines of crimson that defined half his heart.

It's a start—a semi-conscious choice that connects them where so many uncontrolled forces have so far. Caitlin laughs and the sound, the way it radiates through her entire face, chases away the ever-present ache in his hand. "I wonder if everyone feels like that?"

"My mom's favorite color was midnight blue." don is a little quieter, but it holds a little more significance—a real part of himself offered to her, careful but offered nonetheless. "The color of the sky around the stars," he adds, clarifying. "Theirs were golden."

"My parents' is blue," she mentions after a pause, like she's testing the words on her tongue before she decides to give them up. They soften the smile on Barry's face, train his eyes back to her (not that they stray much; it's only been a few weeks but she's already become his homing beacon, his barometer for every situation). "Quill pens—dad's an archivist and mom just loves to read."

"My mother used to read me Peter Pan before bed each night," a book he's never finished.

"That's one of my dad's favorites."

They're silent for a long moment, tentatively taking one another in, basking in the minute connections, the tiny threads that have been stitching them together for far longer than they'd ever realized. He wants to say more, is searching for words, but Caitlin stands suddenly, abandons her chair for the stool nearest his bed. She says nothing as she scrolls through the monitors, begins to check his bandages and carefully test his healing. "I'm glad you're okay," warms his arm, as she prods gently along his wrist, close enough to hear the wobble behind her words.

"I'm glad I'm here," and he's nothing but soft smiles when her eyes teeter back to his.

 

It's been years since Caitlin buried her hopes and dreams of something as frivolous and impossible as soul mates and destiny, tucked them away like all the other remnants of childlike faith. And yet, suddenly, the idea is real again, a concrete possibility, tangible and visible, and it's thrilling and frightening all at once. It's real, Barry is real: twelve crimson lines scattered precisely across the otherwise smooth flesh above his collarbone, a perfect match for the ones curled around the inside of her wrist.

She's spent months avoiding it, but now he's breathing and watching her with eyes as green as late spring grass, too intent to hide an ounce of the marvel that glitters behind them.

"I was beginning to think I'd never meet you," he starts, tentative, into the silence that's settled around them since Wells and Cisco left for the lower lab. "That maybe someone got it wrong and I didn't have a..." he trails off and she's torn (grateful and longing, afraid and excited, such a wide world of possibilities she'd shuttered off for so long).

"I thought that too," she admits, finally, edging into his balance, likes pieces settling into place (she's spent years scoffing the whole institution, but it's impossible to deny the way every part of her practically sings synergy, thrumming with the connection). "Especially when I fell in love with Ronnie," it's still not easier, more than a year later. She still stumbles over his name, still loves him, and Barry seems to understand that, rushes across the space between them to carefully curl his fingers against her elbow, drawing her attention back in.

"It's okay," and it is, she knows it, can feel it (his sincerity, his worry, the slow but sure shoring up of affection). "This is whatever we need, right? Right now you don't need anyone to love," her lip catches between teeth, a knot of anxiety loosening but still tangled somewhere near her heart, "just someone to be there. I can do that." It works mostly free, and the knot must have been connected to the corners of her mouth, because they turn up softly, her dark eyes finding his.

"Thank you Barry," it means a lot, that he understands (she's still grieving, but for the first time since it all happened, it feels like maybe she won't always be).

"Of course, always, I mean it." It's a little breathless, the way the promise spills out around his lips and that should be weird but she knows she'd say the same and mean it equally, so it's really not.

There's a catch in her throat, something a bit too tight, so Caitlin nods and Barry smiles back, careful and tentative but so ridiculously fond and it leaves her a little flustered, to be the center of that much easy affection. As they've done so many times in the past, the fingers of her free hand begin to slide against the watch band covering her mark and it catches Barry's attention immediately—his smile melts into something more intense, something hyper focused and his own fingers reach out without him even seeming to understand what he's doing.

"Can I see it?" The question is a shadowed whisper, an impulsion he's trying to fight for worry it will bother her but she's surprised to find she doesn't mind.

Instead of answering, Caitlin's thumb finds the end of the band, pushes it up to release the pressure and lets the whole watch fall to her palm. The intensity of his focus tears a shiver up her spine and once again, his digits have a mind of their own, skirting with a scarce ghost of pressure along her forearm: closer and closer until they stutter to a stop. "Is it okay, may I?"

She wants to say no a little bit, draw some sort of line between them, but then she looks up to take in his expression: his brown is furrowed, mouth pulled taught with concentration and there's something behind his eyes (yearning? longing? disbelief?) that resonates deep in her chest. "Yes," as if the clipped, careful syllable will gather any sense of order amongst her frayed emotions.

It doesn't, or if it does, they burn up entirely as the tips of his fingers brush along the lines of her mark for the first time, a jolt of electricity that courses through every nerve ending and cell. It's all she can do to hold air in her lungs (she's chewing most of her lip now, with the force of holding something in). "It's beautiful," as if he hasn't seen it every day of his life, echoed on his own flesh.

She wonders. "Can I," there's a pause, a second of second thoughts that burning curiosity set to useless flame. "Can I see yours?"

 

Her soul mate courts death like a lover, takes risks like they’re oxygen and it leaves her frayed and frustrated on the best of days (she cares about him, they're friends and it is hard, so hard, to watch him run headlong into danger knowing he'll just wind up back on the medical table a few hours later, victorious but bleeding).

At first it’s merely annoying, drawing her scoffs and her scorn when he and Cisco try and hide it from her (poorly; she's not sure which is the worse liar) but the months drag by with their highs and lows (bad guys and good guys littered between their building friendship, quiet shared moments and brief, comforting touches) and it quickly becomes anxiety inducing more than anything. She can't forget the way Ronnie looked when he went into the accelerator to save the day and even though Barry has said it before (he's not Ronnie), she can't help the way her pulse spikes every time he speeds off cloaked in red leather and foolish optimism.

Still, he comes back and he heals and he learns how to reassure her (notices how she bites her lip when she's worried, how she rolls her eyes when she's trying not to laugh, how she takes her tea and dog-ears her favorite passages of her favorite books) and they get closer. She figures out the way his fingers drum along his thighs when he's nervous, how they retreat to his pockets when he's stalling, how his eyes crinkle just before he grins and how many sugar packets he prefers in his coffee (an inadvisable amount by anyone's standards—he always laughs fondly when she huffs this at him).

It's progress: slow and steady and sincere (he sidles into her heart far less dramatically then he did her life).

And then, one night, it all shatters open.

He's fighting with some maniac Cisco's taken to calling Savitar, whose powers feel disconcertingly similar to Barry's.

They've been after him for weeks now, the meta human appearing now and then, just long enough to wreak havoc and draw the Flash out before disappearing and Barry's frustration has been mounting with every encounter (clearly Savitar's intention all along).

They're locked in a speed battle now, so fast that Caitlin, Cisco and Dr. Wells hardly know what's happening before it's over: static on the mics interrupted by a sudden groaning, pained and pinched and then stifled with a crunch, before being replaced by a smug voice. "You might want to come and collect your hero," it echoes, cold, over the line, "or what's left of him."

Caitlin is frantic while Cisco calls Joe, who's nearer by and ready to intervene. He's still bleeding by the time they get to STAR Labs, covered in bruises and lacerations that together should be fatal (and would be, on anyone else). Caitlin's hands shake right up until she picks up her sutures and needles and gets to work, cutting and cleaning and stitching with an intensity that never falters (not one tremor, no single tear). The others hover just behind her, wise enough not to interrupt until she's finished.

Barry's still out when she does, but his vitals are improving and she can see the quick effects of his healing, knitting his skin back together, so she sinks onto the stool and promptly loses it the second she exhales and notices the blood coating her gloves and her lab coat and, in some places, the clothing beneath.

"Cait," Cisco starts, gentle and as worried for her as he is for Barry. "Why don't we get you cleaned up?" She's shaking violently while Cisco leads her away, oblivious to the looks the two older men trade.

Half an hour later, she's clean and largely steady when she sinks into the armchair Joe's moved to Barry's bedside. She reaches for his hand as soon as she's settled, weaving their fingers carefully together before exhaustion overcomes her.

It takes Barry another hour to wake up, but when he does, Caitlin is the first thing he sees, guilt wrenching sharply through his chest at the sight of her. She’s still sleeping, curled up in the cramped chair, tiny makeup stains lingering from her tears and wearing a spare set of STAR labs sweats (it’s not hard to imagine what happened to the dress she wore to the lab, given the bandages he’s covered in).

"Caitlin," he whispers, noting that everyone else seems out of the lab for the moment. She doesn't wake up, is clearly exhausted, so Barry gently pulls his fingers loose and moves to swing around on the bed. It hurts: a dozen aches and protests that he steadfastly ignores to get his feet on the ground and then his arms under his still slumbering (beautifully stubborn) soul mate. Somehow he manages it, gets her to the couch in the lounge, but then gets stuck when his back twinges setting her back down.

"Ouch," he hisses, trying to stifle the sound between clenched teeth but apparently still loud enough to wake Caitlin.

Her eyes flutter sleepily for a moment before snapping open, alarmed. "Barry! You should be in bed!"

His smile is as fond as the roll of his eyes. "So should you."

"Seriously," she's sharp now, annoyed as she sits up on the couch. "You should be resting and recovering..." and here she falters, sagging beneath the weight of almost losing him. "You almost died."

"I'm sorry." And he is, because he knows her history and knows that it isn't fair to her. Her eyes skitter toward the floor, not quickly enough to hide the tears that pool behind them. "Oh God Cait, I'm so sorry." She's already crying by the time he gets her in his arms, big tears that shake her entire frame and echo through the small side room.

"I can't do this," she breathes, ragged. "I can't lose someone again Barry Allen, I can't lose you." Ronnie had been horrifying, heartbreaking, but Ronnie had not been her soul mate, much as she loved him.

"I know, I know," Barry mumbles, bringing his hands up to frame her face, palming her jaw and thumb brushing away the steady stream of tears. He does know. The thought of her (whoever she may have been) was the only thing that kept him moving forward after everything happened with his parents, he cannot imagine living through the pain of losing a soul mate (saw exactly how it drained all the fight from his father). "You won't, I'll never do that to you," whatever it takes, he promises himself. She's his center and his life and his first priority.

They shake together a while, still clung close until, gradually, the shock of the day fades a little and the twin pressure in their chests dies away some. His eyes reach for hers, dozens of promises he can't be sure he'll keep tangled in the emerald, and presses their foreheads and noses together, just breathing the same air for a long moment before he eases closer.

Her eyelashes flutter above the pained pull of her mouth, but they hold his steady and she leans in too.

In some ways, it’s rough and desperate, thick with tears and worries and months of slowly built longing, but there's still something insanely them about the kiss (the way they fall together slowly, inch by inch, hesitant but finally, finally ready).

Her scent is still there, that reassuring hint of lily that's come to calm him like nothing else and his gentle way of edging into her gravity is there as well, like he's trying to give her every piece of his soul without forcing it upon her (she already has it, has for months but she gives her own back to him, fully, for the first time when she reaches back for a second kiss after they've drawn away).

"I'm sorry," she mumbles when they part again (for panicking, for worrying, for not being there: he's not sure which but he knows it's not for kissing him).

"I love you," because he can't possibly not say it now.

Somewhere beneath his fingers, he feels the last of the tension drain from her muscles as she falls against him, face buried against his neck. "I love you too."

It sounds like an admission, a promise, a prayer—like destiny.

 

When he was a little boy, his mother told him fantastic stories about soul mates and destiny, about love and friendship and tattoos that melded two hearts into one. He'd listen to her stories with rapt fascination, little fingers tracing dutifully along the crimson pattern on his collar that held his own mark, dreaming of a person who shared those twelve little lines and the other piece of his soul and wondering how (and when) they'd meet.

He never expected the hardships and heartbreak that would separate them, but he also could not have imagined how worthwhile they would feel, curled up in bed with Caitlin's fingers, long and lithe and gentle, tracing the crimson symbol pensively while he relays his mother's stories, her smile quiet and soft (the perfect summary of his whole heart and world and happiness).

"She sounds wonderful," Caitlin murmurs, looking up from his tattoo to catch his gaze.

"She was," Barry agrees, his own fingers wandering until they brush her mark where it lays, unhidden, on her wrist. "She would have loved you."

Caitlin's smile lengthens as she stretches against his chest, inching closer. Leaning down, she presses a chaste kiss against his collarbone (even months after their first kiss, each one sends electricity through his heart in a way that his speed never does) before making her way to meet his mouth, a languid embrace that says they have all the time in the world (a lifetime, he hopes, with an extra hammer against his ribcage, thoughts momentarily distant). "She would have been a little biased," Caitlin teases when she pulls away, scrunching her nose the way she does when she's being playful.

Barry's laugh shakes them both where she's still tangled against him. "Only because she would've loved anyone I did and you make me so happy."

It's still strange for her, sometimes: all his open, easy affection. It's so at odds with the loneliness of her younger years (high school and college, surrounded by people but so different from them all) that she still pauses now and then, as if stunned by how it's all happened (how damn happy she is). It's getting better though, she barely pauses for the span of a heartbeat before she's laughing too, so brightly her eyes sparkle where they hold his. "Good thing you're so easy to please."

She means it as an affectionate joke, something she's teased him about dozens of time, but the second the words fall into the air between them, Barry's expression turns serious (despite herself, she worries; loss is not so distant a visitor that it doesn’t still knock against her heart whenever it seems to please). "Barry?"

Something about his expression settles, resolute and then he's sitting up in their bed and tugging her up along with him, so that they're pressed against the headboard, his fingers finding and tangling with hers. "Maybe not that easy to please, Cait." There's a telltale breeze and a ruffle, just the smallest disturbance to let her know he's flashed away and back already, gripping her hands once more.

"Listen, I love you Caitlin Snow and nothing will ever, ever change that." She nods, brow creasing: of course not, she’s his and he’s hers, soul mates. "So if this is too much, too soon, then that's okay. All I really need is you, but that being said," his right hand leaves hers, to dig at something he's obviously just tucked beneath their sheets: a simple black box that shakes between his fingers, "You're the twelve lines that have been branded, body and soul, across my heart since the day I was born and will be until the day I die. The twelve lines that held me together through my hardest days, that guided me to the home I've found in you and I want to marry you, someday, whenever you're ready," his other fingers untangle from hers now, flip open the lid to a simple silver engagement ring set with a crimson stone. "Marry me?"

The tears pool behind Caitlin's eyes even as a smile stretches across her face (it's not the first time she's been proposed to, but for the first time in a long time, the pain of the past doesn't haunt the life she's living in this moment). Her shaking fingers reach for Barry's face, sliding to gather at the back of his neck and pull him forward for a lingering kiss (it feels a lot like the first one: clinging and rough, gentle and hesitant, a promise and a prayer—destiny).

"Yes."

**Notes for the Chapter:**

> This is the longest continuous fic I've ever written and I'm fairly proud with how it turned out but I very much hope you folks like it as well. I will probably write some bits and pieces to go with it at some point, but those will be bonuses, this is otherwise very much finished.
> 
> If you're looking for a soundtrack to this story, I'm fairly certain I played Ed Sheeran's Tenerife Sea at last 100 times (judging by my iTunes play count) while writing this. Also, if you watch Code Black, their first kiss was somewhat inspired by the Neal/Christa kiss an episode or two ago.
> 
> Feedback is always appreciated and welcome, thanks for following along on this and all my ventures!
> 
> Best Wishes!

**Author's Note:**

> This main fic will be three parts long. Part II will focus on Barry and be about the same length: it should be out on Tuesday sometime. Part III, which will be published on Thursday or Friday (school life pending) will be much longer and focus on 7 key scenes bringing them together. Everything is already written, so minus a little final editing, there should be no delays.


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